Fiber Element Offset Length-Based Optical Reflector Peak Analysis

The present application claims priority under 35 U.S.C. 119(a)-(d) to European Patent Application No. 21306267.2, having a filing date of Sep. 14, 2021 and is and is a Continuation of U.S. patent application Ser. No. 17/943,594, filed Sep. 13, 2022, the disclosure of which is hereby incorporated by reference in its entirety.

An optical time-domain reflectometer (OTDR) is an optoelectronic instrument used to characterize an optical fiber. The OTDR may inject a series of optical pulses into an optical fiber under test. Based on the injected optical pulses, the OTDR may extract, from the same end of the optical fiber in which the optical pulses are injected, light that is scattered or reflected back from points along the optical fiber. The scattered or reflected light that is gathered back may be used to characterize the optical fiber. For example, the scattered or reflected light that is gathered back may be used to detect, locate, and measure events at any location of the optical fiber. The events may include faults at any location of the optical fiber. Other types of features that may be measured by the OTDR include attenuation uniformity and attenuation rate, segment length, and location and insertion loss of connectors and splices.

For simplicity and illustrative purposes, the present disclosure is described by referring mainly to examples thereof. In the following description, details are set forth in order to provide an understanding of the present disclosure. It will be readily apparent however, that the present disclosure may be practiced without limitation to these details. In other instances, some methods and structures have not been described in detail so as not to unnecessarily obscure the present disclosure.

Throughout the present disclosure, the terms “a” and “an” are intended to denote at least one of a particular element. As used herein, the term “includes” means includes but not limited to, the term “including” means including but not limited to. The term “based on”means based at least in part on.

According to examples of the present disclosure, fiber element offset length-based optical reflector peak analysis apparatuses and methods for fiber element offset length-based optical reflector peak analysis are disclosed herein, and provide for implementation of an automated centralized fiber test process using fiber element offset length to enable optical reflector peak identification in an equidistant fiber termination drop environment. The apparatuses and methods disclosed herein may detect reflector peaks, certify, and establish a baseline during build to the last connectivity point in a fiber network where the fiber drop connections to the last termination are equidistant. The apparatuses and methods disclosed herein may utilize an optical element with a pre-set (e.g., controlled) offset length between all n-number of adjacent branches or ports (e.g., staggered optical splitter legs by 5 cm, 10 cm, 50 cm, or another value) to identify, by an optical time-domain reflectometer (OTDR) of a specified resolution, splitter legs in an OTDR trace as peaks in the OTDR trace. For example, for an n-fiber configuration, each of the legs of the staggered leg splitter may be staggered by a value such as 5 cm, 10 cm, etc., so that the splitter terminal connections are similarly staggered. In this regard, instead of the staggered leg splitter, a distribution point or distribution terminal may be utilized for the apparatuses and methods disclosed herein.

With respect to optical fiber testing generally, for an equidistant fiber drop connection, peak reflection from n-number of branches and/or ports of the termination points may be overlaid, and may be undetectable and unidentifiable. This may make it technically challenging for a centralized fiber test system, such as an OTDR, to automatically qualify the n-number of branches and/or ports in a network, such as a passive optical network (PON) network. For example, whereas a single branch of a last demarcation element may be qualified, and peak reflection baselines for this branch may be established, it is technically challenging to identify, qualify, and monitor any adjacent last mile drops on the physical layer. Yet further, with respect to qualification of equidistant n-number of branches of an optical element, a reflector may need to be shifted multiple times based on the number of ports to qualify each branch separately at the test point. Since the branches are equidistant, it may not be possible to leave the reflectors in the original place to see or monitor the reflections on n-number of branches and/or ports (e.g., one branch and/or port may be monitored at one time). Yet further, it is technically challenging to remotely identify the optical termination branch and/or port that the drop fiber has been connected to in order to activate an end of line connection.

The apparatuses and methods disclosed herein address at least the aforementioned technical challenges by implementing an optical element with a pre-set (e.g., controlled) offset length between all n-number of adjacent branches or ports.

According to examples disclosed herein, an optical reflector element may be attached to all n-number of branches to generate an optical signal reflection.

According to examples disclosed herein, the apparatuses and methods disclosed herein may include a centralized optical test head using an ultra-high resolution OTDR to minimize offset lengths corresponding to the OTDR peak resolution. These aspects may reduce the impact of offset length on size of the terminal and optical loss penalty impacts.

According to examples disclosed herein, the apparatuses and methods disclosed herein may include management of automatic peak identification, tagging (e.g., naming), and re-association to enable the qualification and monitoring process of last mile installs.

According to examples disclosed herein, the apparatuses and methods disclosed herein may provide for automatic detection, based on the aforementioned induced offset, of n-number of branches and/or ports terminated with a reflector in a single measurement. In this regard, instead of having to qualify each optical fiber in a network separately (e.g., if the end of line drop points are equidistant), a single OTDR measurement may be performed to qualify all optical fibers (e.g., n-number of optical fibers) that include optical reflectors.

According to examples disclosed herein, for the apparatuses and methods disclosed herein, during an end of line drop connection process, an installer may move a reflector from one selected branch and/or port, and install the reflector at the end of line termination point.

According to examples disclosed herein, for the apparatuses and methods disclosed herein, one additional OTDR measurement may enable automatic detection of the removed peak at the particular branch, and re-associate it to the new peak appearing at the end of line termination point. These aspects may enable automatic remote identification and certification of port occupancy and availability.

According to examples disclosed herein, for the apparatuses and methods disclosed herein, since the end of line drop points may be equidistant, the offset peak generation may enable continuous end-to-end monitoring of all coexisting n-number of end of line terminations.

According to examples disclosed herein, the apparatuses and methods disclosed herein may provide for reduction of costs for installers to qualify n-number of branches and/or ports separately based on a single measurement approach as disclosed herein.

According to examples disclosed herein, the apparatuses and methods disclosed herein may provide for full visibility of n-number of branches and/or port statuses that include, for example, optical health, port occupancy, and port availability, thus providing the insight for planning upgrades and additional build out of elements.

According to examples disclosed herein, the apparatuses and methods disclosed herein may provide for the full end-to-end monitoring in an equidistant last mile drop connections environment.

According to examples disclosed herein, the apparatuses and methods disclosed herein may provide for a simplified centralized test process for activation.

1 FIG.A 100 illustrates an architecture of a fiber element offset length-based optical reflector peak analysis apparatus (hereinafter referred to as “apparatus”), according to an example of the present disclosure.

1 FIG.A 100 102 104 102 106 108 102 104 Referring to, the apparatusmay include an optical elementoptically connected to a laser source (e.g., of OTDR) that emits a laser beam. The optical elementmay include a pre-set offset lengthbetween a plurality of adjacent branches. According to examples disclosed herein, the optical elementmay include a staggered leg splitter (e.g., staggered, for example, by 5 cm, 10 cm, 50 cm, or another value) to identify, by the OTDRof a specified resolution, splitter legs in an OTDR trace as peaks in the OTDR trace.

100 104 110 112 108 114 112 6 FIG. The apparatusmay further include the OTDRto generate, based on optical reflection signals received from corresponding optical reflectorsattached to devices under test (DUTs)that are attached to the plurality of adjacent branches, an OTDR trace(e.g., see) that qualifies each of the DUTs.

112 According to examples disclosed herein, the DUTsmay include optical fibers.

104 104 104 According to examples disclosed herein, the pre-set offset length may be based on a resolution of the OTDR. For example, the pre-set offset length may be greater than the resolution of the OTDR. For example, assuming that the resolution of the OTDRis 30 cm, in this regard, the preset offset length may be specified at 50 cm.

1 FIG.A 1 FIG.A 112 116 118 According to examples disclosed herein, as shown in, fiber drop connections to a last termination associated with the DUTsmay be equidistant. For example, as shown in, based on the offset shown, the fiber drop connections to a last termination associated with the DUTsandare equidistant.

114 114 600 602 114 112 114 112 102 6 FIG. According to examples disclosed herein, the OTDR tracemay be qualified by identifying, in the OTDR trace, at least one peak (e.g., see peaksandof) corresponding to the at least one optical reflector. In this regard, the number of peaks expected in the OTDR tracemay be equal to the number of DUTs(or corresponding optical reflectors). Thus, in the event a number of peaks in the OTDR traceis less than the number of DUTs, the DUTs may be separately analyzed, or otherwise, an offset value associated with the optical elementmay be changed to separate the peaks.

According to examples disclosed herein, a network associated with qualification of the at least one DUT may include a passive optical network (PON) network.

According to examples disclosed herein, qualifying the at least one DUT may include identifying the at least one DUT.

According to examples disclosed herein, the pre-set offset length between the plurality of adjacent branches may be uniform. In this regard, the pre-set offset length between the plurality of adjacent branches may be specified as being uniform such that the fiber drop connections to a last termination associated with the DUTs are equidistant.

According to examples disclosed herein, the pre-set offset length between the plurality of adjacent branches may be variable. In this regard, the pre-set offset length between the plurality of adjacent branches may be specified as being variable such that the fiber drop connections to a last termination associated with the DUTs are equidistant.

104 112 114 6 FIG. According to examples disclosed herein, the OTDRmay generate, based on at least one optical reflection signal received from at least one corresponding optical reflector attached to at least one DUT of a plurality of DUTsthat are attached to the plurality of adjacent branches, an OTDR trace (e.g., see OTDR traceof) that qualifies the at least one DUT.

1 1 FIGS.B-E 100 illustrate examples of optical elements for the apparatus, according to an example of the present disclosure.

1 1 FIGS.B-E 1 FIG.B 1 FIG.C 1 FIG.D 1 FIG.E Generally, the examples ofdescribe a fiber element offset length-based optical reflector peak analysis apparatus including an optical element optically connected to a laser source that emits a laser beam. The optical element may include a splice tray that includes DUTs attached to a plurality of adjacent branches (e.g.,), a connected cable stub that includes DUT pigtails for the DUTs (e.g.,), an optical splitter that includes that DUTs (e.g.,), or a test fanout that includes staggered outputs (e.g.,). In this regard, an OTDR may generate, based on optical reflection signals received from corresponding optical reflectors attached to the DUTs that are attached to the optical element, an OTDR trace that qualifies each of the DUTs.

1 FIG.B 102 120 1 122 2 124 126 122 124 127 122 124 123 125 Specifically, referring to, in one example, the optical elementmay include optical fibers spliced in a splice tray as shown at. In this regard, a length of fiber(e.g., at) may be greater than a length of fiber(e.g., at), for example, by 50 cm, with the additional length being stored around the round drum. The fibers atandmay be connected to a splice holder. Further, the fibers atandmay exit the splice tray, for example, atand.

1 FIG.C 102 128 1 130 2 132 134 130 132 135 137 130 132 131 133 Referring to, in another example, the optical elementmay include optical fiber pigtails with connectors or a connected cable stub as shown at. In this regard, a length of pigtail(e.g., at) may be greater than a length of pigtail(e.g., at), for example, by 50 cm, with the additional length being stored around the round drum. The fibers atandmay be connected to a splice holder, and to an adapter panel at. Further, the fibers atandmay exit the connectors or connected cable stub, for example, atand.

1 FIG.D 102 136 138 140 138 140 141 138 140 139 Referring to, in another example, the optical elementmay be formed by an optical splitter with connectors as shown at. In this regard, a length of splitter out 1 (e.g., at) may be greater than a length of splitter out 2 (e.g., at), for example, by 50 cm. The fibers atandmay be connected to an adapter panel at. Further, the fibers atandmay exit the optical splitter, for example, at.

1 FIG.E 102 142 144 146 Referring to, in another example, the optical elementmay be formed as a test fanoutthat may be connected and spliced to an optical element output from one side (e.g., at), and the other side (e.g., at) may have staggered legs and reflector at each leg to create staggered outputs.

2 FIG. 100 illustrates further details of the architecture of the apparatus, according to an example of the present disclosure.

2 FIG. 2 FIG. 114 114 200 202 2 200 202 204 206 208 210 Referring to, the example ofshows an optical distribution network (ODN) construction use case. In this regard, the OTDR tracemay be qualified by identifying, in the OTDR trace, at least one peak (e.g., peaksand) corresponding to the at least one optical reflector. In the example of FIG., the peaksandmay correspond to optical reflectorsandat home locationsand, respectively.

3 FIG. 100 illustrates further details of the architecture of the apparatus, according to an example of the present disclosure.

3 FIG. 300 302 304 102 302 306 102 102 302 Referring to, an optical line termination (OLT)may inject an optical signal at 1490 nm, and an optical transport unit (OTU)may inject an optical signal at 1650 nm via wavelength-division multiplexer (WDM)into the optical element. The OTUmay receive return signals, for example, at 1310 nm from optical network terminals (ONTs). Since the ONTs are equidistant from the optical element, the pre-set offset for the branches of the optical elementprovide for qualification of both ONTs based on a single measurement by the OTU.

4 FIG. 100 illustrates an OTDR trace without reflectors to illustrate operation of the apparatus, according to an example of the present disclosure.

4 FIG. 110 114 400 402 Referring to, without the optical reflectors, the OTDR tracemay include a peak atat a splitter, and noise-type readingsafter splitters.

5 FIG. 100 illustrates an OTDR trace with reflectors to illustrate operation of the apparatus, according to an example of the present disclosure.

5 FIG. 4 FIG. 110 114 500 502 Referring to, compared to, with the optical reflectors, the OTDR tracemay include distinct reflection readingsafter splitters (e.g., at).

6 FIG. 100 illustrates an ultra-high resolution (UHR) OTDR trace to illustrate operation of the apparatus, according to an example of the present disclosure.

6 FIG. 114 114 600 602 114 112 104 104 104 Referring to, as disclosed herein, the OTDR tracemay be qualified by identifying, in the OTDR trace, at least one peak (e.g., peaksand) corresponding to the at least one optical reflector. In this regard, the number of peaks expected in the OTDR tracemay be equal to the number of DUTs(or corresponding optical reflectors). As disclosed herein, the pre-set offset length may be based on a resolution of the OTDR. For example, the pre-set offset length may be greater than the resolution of the OTDR. For example, assuming that the resolution of the OTDRis 30 cm, in this regard, the preset offset length may be specified at 50 cm.

7 FIG. 7 FIG. 100 700 702 704 110 706 illustrates different splitter configurations to illustrate operation of the apparatus, according to an example of the present disclosure Referring to, at, an optical test head may include a reflector on each branch as shown at. At, optical reflectorsmay be placed on some of the branches. Further, at, an optical reflector may be placed on one of the branches, where the optical reflector may need to be moved to qualify an associated DUT.

8 FIG. 100 illustrates further details of the architecture of the apparatus, according to an example of the present disclosure.

8 FIG. 104 102 800 802 804 806 102 Referring to, for an OTDR, a DUT qualification without and with an optical elementis respectively shown atand. In this regard, the OTDR traceshows that peak reflections coexist at the same distance and cannot be distinguished. Alternatively, the OTDR traceshows that peak reflections can be seen even if reflectors are located equidistant from the optical element.

9 FIG. 900 900 104 914 900 shows a computer systemthat may be used with the examples described herein. The computer system may represent a generic platform that includes components that may be in a server or another computer system. The computer systemmay be used as part of a platform for a controller of the OTDR(e.g., OTDR controller). The computer systemmay execute, by a processor (e.g., a single or multiple processors) or other hardware processing circuit, the methods, functions, and other processes described herein. These methods, functions and other processes may be embodied as machine readable instructions stored on a computer readable medium, which may be non-transitory, such as hardware storage devices (e.g., RAM (random access memory), ROM (read only memory), EPROM (erasable, programmable ROM), EEPROM (electrically erasable, programmable ROM), hard drives, and flash memory).

900 902 902 904 909 902 908 906 914 906 902 The computer systemmay include a processorthat may implement or execute machine readable instructions performing some or all of the methods, functions and other processes described herein. Commands and data from the processormay be communicated over a communication bus. The computer system may also include a main memory, such as a random access memory (RAM), where the machine readable instructions and data for the processormay reside during runtime, and a secondary data storage, which may be non-volatile and stores machine readable instructions and data. The memory and data storage are examples of computer readable mediums. The memorymay include the OTDR controllerincluding machine readable instructions residing in the memoryduring runtime and executed by the processor.

900 910 912 The computer systemmay include an I/O device, such as a keyboard, a mouse, a display, etc. The computer system may include a network interfacefor connecting to a network. Other known electronic components may be added or substituted in the computer system.

902 902 100 902 914 The processormay be designated as a hardware processor. The processormay execute operations associated with various components of the apparatus. For example, the processormay execute operations associated with the OTDR controller, etc.

900 916 The computer systemmay include a mobile application interfacethat enables users to control and trigger a measurement process to provide a visual result of the test, and enable peak visualization, identification, association, and re-association.

What has been described and illustrated herein is an example along with some of its variations. The terms, descriptions and figures used herein are set forth by way of illustration only and are not meant as limitations. Many variations are possible within the spirit and scope of the subject matter, which is intended to be defined by the following claims—and their equivalents—in which all terms are meant in their broadest reasonable sense unless otherwise indicated.